Sputtering target and antiferromagnetic film and magneto-resistance effect element formed by using the same

ABSTRACT

A sputtering target consisting essentially of Mn and at least one kind of R element selected from a group of Ni, Pd, Pt, Co, Rh, Ir, V, Nb, Ta, Cu, Ag, Au, Ru, Os, Cr, Mo, W, and Re. The sputtering target, at least as a part of target texture, comprises one member selected from a group of an alloy phase and a compound phase formed between the R element and Mn. In addition, oxygen content in the target is 1 weight % or less (including 0). With such a sputtering target, an anti-ferromagnetic material film consisting of RMn alloy excellent in corrosion resistivity and thermal performance can be stabilized in its film composition and film quality. By employing the anti-ferromagnetic material film, when an exchange coupling film is formed by stacking the anti-ferromagnetic material film and the ferromagnetic material film, sufficient exchange coupling force is obtained stably. Such an exchange coupling film can be used in a magneto-resistance effect element and the like.

TECHNICAL FIELD

This invention relates to a sputtering target, an anti-ferromagneticmaterial film formed using thereof and a magneto-resistance effectelement formed using the same.

BACKGROUND ART

Until now, as a reproducing magnetic head for high density magneticrecording, a magnetic head (MR head) using a magneto-resistance effectelement (hereinafter referred to as MR element) is under study. Atpresent time, for a magneto-resistance effect film (MR film), Ni₈₀ Fe₂₀(atomic %) alloy (permalloy) or the like, which shows anisotropicmagneto-resistance effect (AMR), is generally used. Since the AMR filmpossesses such a small magneto-resistance change rate as about 3% (MRchange rate), as an alternative material for the magneto-resistanceeffect film material, an artificial lattice film and a spin valve filmsuch as (Co/Cu)n and the like, which display giant magneto-resistanceeffect (GMR), are attracting attention.

In an MR element using an AMR film, since the AMR film possessesmagnetic domains, Barkhausen noise resulting from the existence of themagnetic domains becomes a drawback when putting to practical use.Therefore, various means for making an AMR film into a single domain arebeing studied. As one method among them, there is a method in which themagnetic domains in an AMR film is controlled in one particulardirection by utilizing exchange coupling between an AMR film, which is aferromagnetic material, and an anti-ferromagnetic material film. As ananti-ferromagnetic material in this case, γ-FeMn alloy is so far wellknown (see the specification of U.S. Pat. No. 4,103,315, thespecification of U.S. Pat. No. 5,014,147, and the specification of U.S.Pat. No. 5,315,468, for example).

Besides, a spin valve film comprises a sandwich film possessing alaminate structure formed of a ferromagnetic layer/a non-magneticlayer/a ferromagnetic layer, and, by pinning magnetization of oneferromagnetic layer, a GMR is obtained. For pinning magnetization ofanother ferromagnetic layer of the spin valve film, a technologyutilizing exchange coupling between an anti-ferromagnetic film and aferromagnetic film is generally used. For a constituent material of theanti-ferromagnetic material film in this case, γ-FeMn alloy is generallyin use.

However, γ-FeMn alloy is poor in corrosion resistivity. In particular,it is easily corroded by water. Thus, since an MR element utilizing ananti-ferromagnetic material film consisting of γ-FeMn alloy is easilycorroded by, particularly, water in the air during processing step intoan element shape or a head shape, thus, as a result of this corrosion,the exchange coupling force with an MR film tends to graduallydeteriorate in time.

For an exchange coupling film formed between an anti-ferromagneticmaterial film and a ferromagnetic material film, from reliabilityview-point, an exchange coupling force is required to be 200 Oe and moreat, for example, 393 K. To realize an exchange coupling force of 200 Oeand more at 393 K, in addition to an exchange coupling force at roomtemperature, temperature dependency of the exchange coupling force isrequired to be good. Concerning the temperature dependency of theexchange coupling force, a blocking temperature at which temperature theexchange coupling force between a ferromagnetic material film and ananti-ferromagnetic material film is lost is desirable to be high as muchas possible. However, γ-FeMn alloy is as low as 443 K in the blockingtemperature, and also the temperature dependency of the exchangecoupling force thereof is very poor.

Besides, in U.S. Pat. No. 5315468 for example, θ-Mn alloy, such as NiMnalloy, possessing a crystal structure of face-centered tetragonalcrystal system is described as an anti-ferromagnetic material film. Whenan anti-ferromagnetic material film consisting of the θ-Mn alloy isused, it is shown that the exchange coupling force between theanti-ferromagnetic material film and the ferromagnetic material filmdoes not deteriorate.

Further, as an anti-ferromagnetic material film high in a blockingtemperature, large in an exchange coupling force, and excellent incorrosion resistivity, IrMn alloy possessing a crystal structure offace-centered tetragonal crystal system is proposed. Asanti-ferromagnetic material films possessing the same crystal structure,γ-Mn alloy such as PtMn alloy or RhMn alloy other than γ-FeMn alloy isknown (see U.S. Pat. No. 4,103,315, U.S. Pat. No. 5,315,468).

As described above, Mn alloys such as IrMn alloy, PtMn alloy, RhMnalloy, NiMn alloy, PdMn alloy, and CrMn alloy are excellent in corrosionresistivity and further can be enhanced in the blocking temperature ofthe exchange coupling film. Thus, they are attracting attention as ananti-ferromagnetic material capable of enhancing long term reliabilityof the MR element.

Now, as a method for forming an anti-ferromagnetic material film, thesputtering method is generally used. Using a sputtering targetcomprising each element which constitutes the above described Mn alloys,an anti-ferromagnetic material film is formed into a film by asputtering method. However, an anti-ferromagnetic material film formedinto a film with a conventional sputtering target tends to form anonhomogeneous film composition in a formed film plane. In such anexchange coupling film formed between an anti-ferromagnetic materialfilm and a ferromagnetic material film, there is a problem that asufficient exchange coupling force can not be obtained. In addition,there is another problem that an MR element and an MR head which usesuch an exchange coupling film tend to be adversely affected on theanti-ferromagnetic material film from the other constituent films todeteriorate in its exchange coupling performance.

Further, the conventional sputtering target tends to cause a largecomposition deviation between film composition sputtered at the initialstage of sputtering and that obtained at the life end. Such a temporalchange of the film composition of the anti-ferromagnetic material filmcan also cause to deteriorate the exchange coupling performance.

The first object of the present invention is to stabilize a filmcomposition and a film quality of an anti-ferromagnetic material filmcomprising a Mn alloy excellent in corrosion resistivity and thermalproperty, and to provide a sputtering target less in the compositiondeviation up to the life end. The second object of the present inventionis to provide a sputtering target capable of forming withreproducibility an anti-ferromagnetic material film of which exchangecoupling force at the room temperature and high temperature region isstable, and to provide an anti-ferromagnetic material film possessingsuch performance. The third object of the present invention is, by usingan anti-ferromagnetic material film excellent in such performance, toprovide a magneto-resistance effect element which enables to obtainstable performance and stable output power with reproducibility.

DISCLOSURE OF INVENTION

The first sputtering target of the present invention consistsessentially of Mn and at least one kind R element selected from a groupof Ni, Pd, Pt, Co, Rh, Ir, V, Nb, Ta, Cu, Ag, Au, Ru, Os, Cr, Mo, W, andRe, wherein the sputtering target comprises at least one member selectedfrom a group of an alloy phase and a compound phase formed between theabove described R element and Mn as at least a part of the targettexture.

The second sputtering target of the present invention consistsessentially of Mn and at least one R element selected from a group ofNi, Pd, Pt, Co, Rh, Ir, V, Nb, Ta, Cu, Ag, Au, Ru, Os, Cr, Mo, W, andRe, wherein, the sputtering target, as at least a part of targettexture, includes at least one member selected from a group of an alloyphase and a compound phase formed between the R elements and Mn, andoxygen content thereof is 1 weight % or less (including 0).

The first and second sputtering target are further featured in Mn otherthan that constituting the alloy phase and the compound phase possessinga grain diameter of 50 μm and less.

The third sputtering target of the present invention consistsessentially of Mn and at least one kind of R element selected from agroup of Ni, Pd, Pt, Co, Rh, Ir, V, Nb, Ta, Cu, Ag, Au, Ru, Os, Cr, Mo,W, and Re, oxygen content thereof being 1 weight % or less (includes 0).

In a sputtering target of the present invention, it is furtherpreferable that carbon content is 0.3 weight % or less (includes 0) andits relative density is 90% or more. The sputtering target of thepresent invention comprises, for example, 30 atomic % or more of Mn. Thesputtering target of the present invention can further comprise at leastone element selected from a group of Be, Ti, Zr, Hf, Zn, Cd, Al, Ga, In,Si, Ge, Sn, and N.

An anti-ferromagnetic material film of the present invention is formedin a film by sputtering the above described sputtering target of thepresent invention.

The magneto-resistance effect element of the present invention isfeatured in comprising an above-described anti-ferromagnetic materialfilm of the present invention. The magneto-resistance effect element ofthe present invention comprises, for example, the above describedanti-ferromagnetic material film of the present invention and aferromagnetic material film exchange coupled with the anti-ferromagneticmaterial film. Further, the magneto-resistance effect element comprisesthe above described anti-ferromagnetic material film of the presentinvention, a first ferromagnetic layer exchange coupled to theanti-ferromagnetic material film, and a second ferromagnetic layerstacked with the first ferromagnetic layer through a non-magnetic layer.The magneto-resistance effect element of the present invention can beapplied in, for example, a magnetic head. The magneto-resistance effectelement of the present invention can be used in a magnetic recordingapparatus such as a MRAM, and a magnetic sensor.

In the present invention, the R element is distributed in a sputteringtarget as an alloy phase or a compound phase formed between Mn. Bydistributing the R element in a target texture as the alloy phase or thecompound phase formed with Mn, a composition within the target can bemade homogeneous. Further, the target texture can also be made toapproach a homogeneous state. In particular, when a total composition ofa target is rich in Mn, by distributing the R element as the alloy phaseor the compound phase formed between Mn, the composition and the texturecan be enhanced in homogeneity.

Further, by controlling oxygen content in a sputtering target to be 1weight % or less, even when the sputtering target possesses a targetcomposition rich in Mn, high densification thereof can be easilyattained. Reduction of the oxygen content of the sputtering target anddensification thereof largely contribute in purifying and in making lowthe oxygen content of an anti-ferromagnetic material film formedtherewith. Further, they contribute in enhancement of film quality andfilm composition (deviation from the target composition) of theanti-ferromagnetic material film.

By forming a sputtering film of an anti-ferromagnetic material bysputtering the above described sputtering target of the presentinvention, an anti-ferromagnetic material film excellent in homogeneitywithin its film plane can be obtained stably. Further, by homogenizingthe composition and the texture of the sputtering target, thecomposition can be effectively suppressed in deviation from the initialstage of the sputtering target to the life end thereof. The reduction ofthe oxygen content of the sputtering target and high densificationthereof can have the same effect.

As described above, by using the sputtering target of the presentinvention, an anti-ferromagnetic material film excellent in stability ofthe film composition as well as in homogeneity of the film compositionwithin its film plane can be obtained with reproducibility. By formingan exchange coupling film through lamination of such ananti-ferromagnetic material film with, for example, a ferromagneticmaterial film, performance excellent in sufficient exchange couplingforce, good corrosion resistivity, heat resistivity, and the like can beobtained stably.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a cross sectional view showing a structure of one example ofan exchange coupling film using an anti-ferromagnetic material film ofthe present invention.

FIG. 2 is a cross sectional view showing a structure of one example of amagneto-resistance effect element of the present invention.

FIG. 3 is a cross sectional view showing a modification of themagneto-resistance effect element shown in FIG. 2.

FIG. 4 is a cross sectional view showing a structure of another exampleof a magneto-resistance effect element of the present invention.

FIG. 5 is a cross sectional view showing a structure of one example of amagnetic head using a magneto-resistance effect element of the presentinvention.

FIG. 6 is a cross sectional view showing one modification example of amagnetic head shown in FIG. 5.

FIG. 7 is a graph showing composition dependency of exchange couplingforce of anti-ferromagnetic material films formed in films usingsputtering targets formed according to embodiment 3 of the presentinvention.

FIG. 8 is a graph showing results of corrosion resistivity test of theexchange coupling film samples formed into films using the sputteringtargets obtained according to embodiment 7 of the present invention.

FIG. 9 is a graph showing measured results of exchange bias forces ofthe exchange coupling film samples formed into films using thesputtering targets formed according to embodiment 7 of the presentinvention.

FIG. 10 is a graph showing measured results of blocking temperatures ofthe exchange coupling film samples formed into films using thesputtering targets obtained according to embodiment 7 of the presentinvention.

MODE FOR CARRYING OUT THE INVENTION

Embodiments for implementing the present invention will be described inthe following.

As a first example of a sputtering target of the present invention, oneconsisting substantially Mn and at least one R element selected from agroup of Ni, Pd, Pt, Co, Rh, Ir, V, Nb, Ta, Cu, Ag, Au, Ru, Os, Cr, Mo,W, and Re, can be cited. An anti-ferromagnetic material film comprisingRMn alloy formed in a film using a sputtering target of the presentinvention can, by laminating it with various ferromagnetic materialfilms, be used as, for example, an exchange coupling film.

In a sputtering target of the present invention, although Mn content canbe appropriately set based on a combination with the R element, Mncontent is preferable to be set at least at 10 atomic % or more. Whenthe Mn content is too low, excellent exchange coupling force can not beobtained. On the contrary, when the content of the R element is too low,corrosion resistivity tends to deteriorate. Thus, Mn content ispreferable to be set in the range of from 10 to 98 atomic %. The presentinvention is particularly effective for a sputtering target comprising acomposition rich in Mn, such as 30 atomic % or more of the Mn content.

A more preferable range of the Mn content is set based on a selected Relement. For example, when the R element is Ir, Rh, Au, Ag, Co, Ru, Re,it is preferable for the Mn content to be set in the range of from 40 to98 atomic %, and more preferable to be set in the range of from 60 to 95atomic %. An RMn alloy including above described R element generallystabilizes in a crystal structure of a face-centered cubic crystalsystem in the above described composition range. Since an RMn alloycomprising a face-centered cubic crystal structure portion as a partthereof possesses a particularly high Neel temperature (the temperaturewhere an anti-ferromagnetic material loses its anti-ferromagnetism), ablocking temperature of an exchange coupling film can be much improved.

In addition, when the R element is Ni, Pd, thermal stability can beenhanced when the crystal structure takes a face-centered tetragonalcrystal system. Therefore, it is preferable for the Mn content to be setin such a composition range where the crystal structure stabilizes,namely 30 to 70 atomic % of Mn content. When the R element is Cr, theRMn alloy takes a body-centered cubic crystal structure and abody-centered tetragonal crystal structure, and the Mn content ispreferable to be set in the range of from 30 to 70 atomic %. When the Relement is Pt, both a face-centered cubic crystal structure and aface-centered tetragonal crystal structure can be excellent in thermalstability. In this case, the Mn content is preferable to be in the rangeof from 30 to 98%, and more preferable to be in the range of from 60 to95%.

A sputtering target of the present invention can include, other than theabove described R elements, at least one kind of element (A element)selected from a group of Be, Ti, Zr, Hf, Zn, Cd, Al, Ga, In, Si, Ge, Snand N. Although an anti-ferromagnetic material film composed of an RMnalloy can, based on the above described composition range and thecrystal structure, show an excellent corrosion resistivity compared withconventional FeMn alloy, by including such additional components, thecorrosion resistivity can be furthermore enhanced. However, if the Aelement is added too much, the exchange coupling force tends todeteriorate. Compounding quantity of the A element is preferable to beset at 40 atomic % or less, more preferable to be set at 30 atomic % orless.

A sputtering target of the present invention comprises, at least as apart of target texture, at least one member selected from a group of analloy phase formed between the R element and Mn and a compound phaseformed therebetween.

A sputtering target obtained by combining the R element and Mn isgenerally difficult in densifying it with a powder sintering method andthe like, further more difficult in uniformly distributing the R elementagainst Mn. When Mn rich composition range is employed, the distributionof the R element particularly tends to deviate from homogeneity.

In such a combination between the R element and Mn, the R element of thepresent invention is distributed in a sputtering target as an alloyphase or a compound phase formed between Mn. When, for example, Ir isemployed as the R element, IrMn₃ can be cited as a compound phasetherebetween. By distributing the R element into the target texture asan alloy phase or a compound phase rich in Mn and thereby reducing the Relement existing in a single phase down to the minimum level, acomposition among the target can be made homogeneous. Further, thetarget texture (metallurgical texture) also approaches to a homogeneousstate. In particular, when the whole composition of the target is richin Mn, by distributing the R element as an alloy phase or a compoundphase formed therebetween, homogeneity in the composition and thetexture can be improved.

Now, when two kinds or more of element are used as the R element, analloy phase and a compound phase formed between the R elements and Mncan be any alloys or compounds formed either between respective Relement and Mn, or between two kinds or more of R element and Mn. Forexample, when Ir and Rh are selected as the R element, any one or moreof binary alloys or binary compounds formed between Ir and Mn, Rh andMn, and tertiary alloys and tertially compounds formed between Ir and Rhand Mn can exist.

In addition, Mn other than that forming the above described alloy phaseand compound phase can exist as a single phase of Mn. In the presentinvention, although a part of the R element can be allowed to exist as asingle phase, a proportion thereof is, from above described reasons,preferable to be suppressed as small as possible.

Further, other remaining Mn than that forms the above described alloyphase and compound phase is preferable to possesses a grain diameter(grain size) of 50 μm or less. When a diameter of Mn grain remaining ina single phase is large, it can be said that Mn is segregated from amicroscopic view point. To remove nonhomogeneity of the composition andthe texture caused by such a segregation of Mn, Mn grain existing in asingle phase is preferable to possess the maximum diameter of 50 μm orless. In addition, an average diameter of Mn grain is preferable to bein the range of from 10 to 40 μm.

Making Mn grain diameter fine is particularly effective when a targetcomposition is Mn rich. However, since oxygen content may increase ifthe average diameter of Mn grain is too small, it is preferable to setthe average diameter at 10 μm or more. It is more preferable to set themaximum diameter of Mn grain at 30 μm or less. Here, the grain diameter(grain size) of Mn means a diameter of the minimum circle surrounding Mngrain.

By forming an anti-ferromagnetic material film using the above describedsputtering target of the present invention, the anti-ferromagneticmaterial film excellent in homogeneity of film composition in a filmplane can be obtained stably. Making homogeneous the composition of thesputtering target and the texture thereof is also effective insuppressing composition deviation from the initial stage of sputteringto the life-end. As described above, by employing the sputtering targetof the present invention, an anti-ferromagnetic material film excellentin stability of the film composition can be obtained withreproducibility. The obtained anti-ferromagnetic material film isfurther excellent in homogeneity of the film composition in a filmplane.

A sputtering target of the present invention is further preferable toinclude 1 weight % or less (including 0) of oxygen in the sputteringtarget. When the oxygen content of the target is too large, compositioncontrol of Mn particularly during sintering becomes difficult and alsothe oxygen content of the anti-ferromagnetic material film formed by asputtering filming method can increase. These may cause deterioration ofperformance of the anti-ferromagnetic material film. Further, if theoxygen content is large in the target, densification of the targetbecomes difficult. Further, in addition to bad processability, thetarget tends to cause crack during sputtering. More preferable oxygencontent is 0.7 weight % or less, 0.1 weight % or less is morepreferable.

Further, if a carbon content in a target is too large, defect such ascrack tends to occur during sintering and plastic forming. In addition,such performance as an exchange coupling magnetic field and a blockingtemperature of the obtained anti-ferromagnetic material filmdeteriorates. Therefore, the carbon content in the target is preferableto be set at 0.3 weight % or less (including 0). More preferable carboncontent is 0.2 weight % or less, and 0.01 weight % is furtherpreferable.

In particular, by reducing the oxygen content and carbon content in asputtering target, even if the target composition is rich in Mn, thetarget can be densified easily. Further, making the sputtering targetlow in oxygen content and low in carbon content contributes in enhancinghigh purification, film quality, and film composition (deviation fromthe target composition) of the anti-ferromagnetic material film formedin a film using the sputtering target. These can improve suchperformance as an exchange coupling magnetic field of theanti-ferromagnetic material film and a blocking temperature thereof.

A density of the sputtering target of the present invention ispreferable to be 90% or more based on the relative density of thesputtering target. If the density of the sputtering target is too low,particles tend to occur during sputtering due to irregular discharge atdefective portions. If the particles is dispersed in theanti-ferromagnetic material film, in addition to deterioration of theperformance, yield can also be decreased. More preferable relativedensity is 95% or more.

In addition, in the sputtering target of the present invention, bysatisfying anyone among constitution in which a part of the targetcomposition is formed in the alloy phase or compound phase, andconstitution in which the oxygen content is reduced to 1 weight % orless, at least desired effects can be obtained. However, it isparticularly preferable to satisfy both of these constitutions.

For manufacturing the sputtering target of the present invention, bothof a sintering method and a melting method can be applied. However, whenconsidered manufacturing cost and raw material yield, it is preferableto employ the sintering method.

When applying the sintering method in manufacturing of the sputteringtarget of the present invention, firstly, for obtaining the abovedescribed target texture (metallurgical texture which comprises alloyphase and compound phase), raw material powder as fine as possible(respective raw material powder of the R elements and Mn) is preferableto be employed. For example, by employing the R element powder, such asfine Ir powder, and fine Mn powder, homogeneous mixture state can beobtained prior to sintering and reaction between the R elements and Mncan be enhanced. These contribute for increasing production quantity ofthe alloy phase and compound phase formed between the R elements and Mnduring sintering. Further, it is effective in making fine the graindiameter of Mn remaining as a single phase.

However, when the particle diameters of the respective raw materialpowder of the R elements and Mn are too small, the oxygen content in theraw material stage increases to cause increase of the oxygen content inthe target. In particular, since Mn tends to absorb oxygen, it isdesirable to set the particle diameter considering this. Consideringthese, it is preferable to set average particle diameters of the rawmaterial powder of the R elements in the range of from 20 to 50 μm.Besides, average particle diameter of Mn raw material powder ispreferable to be set at 100 μm or less, particularly preferable to beset in the range of from 40 to 50 μm.

Next, the raw material powders of the above described R elements and Mnare compounded at a predetermined proportion, and are fully mixed. Forexecuting mixing operation of the raw material powders, various types ofknown mixing method such as ball mill, V-mixer can be employed. In thiscase, it is important to set mixing condition so as to avoidcontamination from metal impurities as well as to avoid the increase ofoxygen quantity. Concerning the oxygen in the raw material powder, inorder to further reduce it, a small quantity of carbon can be employedas a deoxydizing agent. However, since carbon itself can causeperformance deterioration in a film form anti-ferromagnetic materialfilm, as described above, it is preferable to set the condition that thecarbon content in the target is at 0.3 weight % or less.

For example, when ball milling is employed, in order to avoidcontamination from metal impurities, a container and balls composed ofresin (Nylon, for example) or an inside lining by friendly material suchas same material with the raw material powder are preferable to beemployed. In particular, it is preferable to employ material identicalin quality with the raw material powder. Further, during mixing, toprevent adsorption or absorption, by the raw material powder, of gascomponents confined in the container from occurring, the inside of themixing container is preferable to be a vacuum atmosphere or anatmosphere replaced by an inert gas. When a mixing method other than theball milling method is employed, the identical preventive methods toavoid the contamination from the impurities are preferable to beimplemented.

The mixing duration is appropriately set according to the mixing method,input powder quantity, mixing container capacity, and the like. If themixing duration is too short, homogeneously mixed powder may not beobtained. On the contrary, if the mixing duration is too long, theimpurity quantity tends to increase. Thus, the mixing duration isappropriately determined considering these. For example, when mixingoperation is executed with the ball milling method under a condition ofa mixing container of 10 liter capacity and 5 kg of inputted powder, themixing duration is appropriate to be set at around 48 hours.

Next, a target raw material is obtained by sintering the mixed powderbetween the raw material powder of the above described R elements andthe raw material powder of Mn. The sintering is preferable to beexecuted with a hot-press method or a HIP method thereby a sintered bodyof high density can be obtained. Although the sintering temperature isdetermined according to the type of the raw material powder, to enhancethe reaction particularly between the R elements and Mn, it ispreferable to be set in the range of from 1,150 to 1,200° C. which isimmediately below the melting temperature of Mn (1,244° C.). Bysintering the mixed powder under at such a high temperature, quantity ofthe alloy phase or the compound phase formed between the R elements andMn can be increased in the sputtering target. That is, the R elementsexisting in a single phase can be reduced. The pressure duringhot-pressing and HIPping is preferable to be set at 20 MPa or morethereunder the sintered body can be made dense.

The obtained target raw material is mechanically processed into apredetermined shape. By bonding this to a backing plate with, forexample, a low melting solder, a sputtering target of the presentinvention can be obtained.

By employing such a sintering method that satisfies the above describedconditions, at lower manufacturing cost than a melting method laterdescribed, a sputtering target, in which the alloy phase or the compoundphase between the R elements and Mn exist and the oxygen content and thecarbon content are reduced, can be manufactured stably. In addition,there is another advantage that, when the sintering method is used,yield of rare metal raw material is higher than when the melting methodis employed.

When a sputtering target of the present invention is produced byemploying a melting method, at first, mixed raw material obtained bymixing the R elements and Mn at a predetermined proportion is melted.For melting the mixed raw material, a conventional induction typeelectric furnace can be employed. When melting operation is executedwith an induction method, in order to enhance volatilization of theimpurities, it is preferable to be melted under a reduced pressure (in avacuum atmosphere). However, when composition variation due to thevolatilization of Mn and the like is desired to be suppressed, themelting in an inert gas atmosphere can be implemented. Further,depending on the shape of the raw material, an arc melting method or anelectron beam melting method can be applicable.

An ingot obtained with the above described melting method is, afterplastic forming for example, mechanically processed into a predeterminedtarget shape. By bonding this to a backing plate with a low meltingsolder, a sputtering target of the present invention can be obtained. Byemploying the melting method as well, as identical with the abovedescribed sintering method, a sputtering target, in which the alloyphase or the compound phase formed between the R elements and Mn existand both of the oxygen content and the carbon content are reduced, canbe produced.

An anti-ferromagnetic material film of the present invention can be, byemploying the above described sputtering target of the presentinvention, formed into a film by a conventional sputtering method. Theanti-ferromagnetic material film formed by using the sputtering targetof the present invention is excellent, as described above, in stabilityof the film composition and in the homogeneity of the film compositionin the film plane as well. When it is used as an exchange coupling filmby stacking it with a ferromagnetic material film, such ananti-ferromagnetic material film is formed excellent in performance suchas sufficient exchange coupling force, good corrosion resistivity, andgood thermal resistance with stability.

An anti-ferromagnetic material film of the present invention can be usedas an exchange coupling film by stacking, for example, with aferromagnetic material film. FIG. 1 is a diagram showing schematicallyone example of an exchange coupling film obtained employing ananti-ferromagnetic material film of the present invention. An exchangecoupling film 2 formed on a substrate 1 comprises a stacked film of ananti-ferromagnetic material film 3 and a ferromagnetic material film 4.The stacked film can be formed in such a manner that theanti-ferromagnetic material film 3 and the ferromagnetic material film 4are at least partially stacked to cause exchange coupling therebetween.

In addition, if a condition causing an exchange coupling is satisfied, athird layer can be interposed between the anti-ferromagnetic materialfilm 3 and the ferromagnetic material film 4. Further, an order forstacking the anti-ferromagnetic material film 3 and the ferromagneticmaterial film 4 can be determined according to usage, and theanti-ferromagnetic material film 3 can be formed as an upper side. Anexchange coupling material film can be formed by stacking a plurality ofthe anti-ferromagnetic material films 3 and the ferromagnetic materialfilms 4.

A film thickness of the anti-ferromagnetic material film 3 consisting ofRMn alloy (or RMnA alloy) is, not limited to a particular value if it isin the range causing anti-ferromagnetism, in order to obtain a largeexchange coupling force, preferable to be set at a thickness thickerthan that of the ferromagnetic material film 4. When theanti-ferromagnetic material film 3 is stacked above the ferromagneticmaterial film 4, from a view point of stability of the exchange couplingforce and the like after heat treatment, the thickness thereof ispreferable to be in the range of from 3 to 15 nm, and more preferable tobe set at 10 nm or less. In addition, the thickness of the ferromagneticmaterial film 4 is, from the identical view point, preferable to be inthe range of from 1 to 3 nm. On the contrary, when theanti-ferromagnetic material film 3 is stacked underneath theferromagnetic material film 4, the thickness of the ferromagneticmaterial film 3 is preferable to be in the range of from 3 to 50 nm, andthat of the ferromagnetic material film 4 is preferable to be in therange of from 1 to 7 nm.

For the ferromagnetic material film 4, a ferromagnetic layer of varioustypes of single layer structures composed of Fe, Co, Ni, or alloystherebetween, a magnetic multiple layer film and a granular film whichshow ferromagnetic property can be employed. Specifically, ananisotropic magneto-resistance effect film (AMR film) and a giantmagneto-resistance effect film (GMR film) such as a spin valve film, anartificial lattice film, and a granular film can be cited. Among theseferromagnetic materials, since, by stacking, particularly, Co or Coalloy with an anti-ferromagnetic material film 3 comprising RMn alloy,an exchange coupling film 2 exceedingly high in the blocking temperaturecan be obtained, thus it is favorably employed.

The exchange coupling film 2 of the above described example can beeffectively used for elimination of Barkhausen noise of theferromagnetic material film in a magneto-resistance effect element (MRelement) or for fixation of magnetization of the ferromagnetic materialfilm in an artificial lattice film or a spin valve film. However, usageof the anti-ferromagnetic material film and the exchange coupling film 2using that is not limited to the MR element, but is also applicable invarious ways, for example, such as in regulation of magnetic anisotropyin various magnetic circuit such as a magnetic yoke consisting of theferromagnetic material film.

Next, an example of a magneto-resistance effect element (MR element)using the above described exchange coupling film will be explained withreference to FIG. 2 through FIG. 5. Although the MR element is effectivein, for example, a reproducing element of a magnetic head for magneticrecording apparatus such as a HDD, or a magnetic field detecting sensor,it is also applicable effectively in, other than that described above, amagnetic memory apparatus such as a magneto-resistance effect memory(MRAM=Magnetoresistive random-access memory).

FIG. 2 is one example structure of an AMR element 5 in which theexchange coupling film of the present invention is employed forelimination of the Barkhausen noise of the anisotropicmagneto-resistance effect film (AMR film). The AMR element 5 comprisesas the ferromagnetic material film an AMR film 6 consisting of aferromagnetic material such as Ni₈₀ Fe₂₀ and the like which electricresistance varies depending on an angle formed between a direction ofelectric current and a magnetic moment of the magnetic film. On bothedge portions of the AMR film 6, anti-ferromagnetic material films 3 arestacked, respectively. These AMR film 6 and anti-ferromagnetic materialfilm 3 constitute an exchange coupling film, and, to the AMR film 6, amagnetic bias is invested from the anti-ferromagnetic material film 3.

In addition, on both edge portions of the AMR film 6, a pair ofelectrodes 7 consisting of Cu, Ag, Au, Al, or alloys formed therebetweenand electrically connected to the AMR film through theanti-ferromagnetic material film 3 are formed, and, through this pair ofelectrodes 7, an electric current (sense current) is provided to the AMRfilm 6. These of an AMR film 6, anti-ferromagnetic material films 3, anda pair of electrodes 7 constitute an AMR element 5. Further, theelectrodes 7 can be formed so as to form a direct contact with the AMRfilm 6. Still further, these constituent elements are formed on one mainsurface of the substrate 1 consisting of, for example, Al₂ O₃.TiC.

In the above described AMR element 5, by utilizing an exchange couplingbetween the AMR film 6 and the anti-ferromagnetic material film 3,magnetic bias is given to the AMR film 6 to control magnetic domain,and, by controlling the magnetic domain of the AMR film 6, occurrence ofthe Barkhausen noise is suppressed. Investment of the magnetic bias tothe AMR film 6 through the anti-ferromagnetic material film 3 can be, asshown in FIG. 3, implemented by forming the anti-ferromagnetic materialfilm 3 on the AMR film 6 in a stacked manner through an exchange biasmagnetic field controlling film 8, thereby forming exchange couplingbetween these AMR film 6 and the anti-ferromagnetic material film 3through the exchange bias magnetic field control film 8. In this case, apair of electrodes 7 can be partially stacked at both edge portions ofthe anti-ferromagnetic material film 3.

When the anti-ferromagnetic material film of the present invention isused in investment of the magnetic bias to the AMR film 6 of the AMRelement 5, since, as described above, fundamental performance of theanti-ferromagnetic material film 3 comprising of RMn alloy and the likecan be fully and stably exhibited and since the exchange coupling forcesufficient at room temperature and high temperature region can be stablyobtained, the occurrence of the Barkhausen noise can be suppressed withreproducibility under various conditions.

FIG. 4 shows one construction example of a GMR element 9 manufactured byapplying the anti-ferromagnetic material film of the present inventionfor fixing magnetically the ferromagnetic layer of a giantmagneto-resistance effect film (GMR film). The GMR element 9 comprises,as the ferromagnetic material film, a multi-layered film of sandwichstructure formed between a ferromagnetic layer/a non-magnetic layer/aferromagnetic layer, a multi-layered film formed by stacking a spinvalve film, in which electric resistivity varies depending on an angleformed between magnetizations of these ferromagnetic material films, orthe ferromagnetic layer and the non-magnetic layer, and a GMR film 10comprising an artificial lattice film displaying GMR.

A GMR element 9 shown in FIG. 4 comprises a GMR film (spin valve GMRfilm) 10 comprising a spin valve film. This spin valve GMR film 10possesses a sandwich structure formed of a ferromagnetic material layer11/a non-magnetic layer 12/a ferromagnetic layer 13, wherein on theupper side ferromagnetic layer 13 an anti-ferromagnetic material film 3is laminated. The ferromagnetic layer 13 and the anti-ferromagneticmaterial film 3 constitute an exchange coupling film. The upper sideferromagnetic layer 13 is a so-called pinning layer which ismagnetically fixed through an exchange coupling force with theanti-ferromagnetic material film 3. Besides, the lower sideferromagnetic layer 11 is a so-called free layer varying in amagnetization direction according to a signal magnetic field (externalmagnetic field) from a magnetic recording medium and the like. Inaddition, in the spin valve GMR film 10, the pinning layer and the freelayer can be upside-down in their positions.

The ferromagnetic layer 11 can be formed on a magnetic substrate layer(or non-magnetic substrate layer) 14 depending on necessity. Themagnetic substrate layer 14 can be formed of one kind of magnetic filmor a laminate film of different kinds of magnetic films. Specifically,as a magnetic substrate layer 14, an amorphous type soft magneticmaterial or a soft magnetic material of a face-centered cubic crystalstructure, such as NiFe alloy, NiFeCo alloy, and magnetic alloys addedthereto various kinds of additional elements can be used. Further, inthe figure, numeral 15 shows a protective film consisting of Ta and thelike be formed depending on necessity.

On both edge portions of the spin valve GMR film 10, a pair ofelectrodes 7 are formed of Cu, Ag, Au, Al, or alloys formed therebetweenand from a pair of electrodes an electric current (sense electriccurrent) is provided to the spin valve GMR film 10. From these of thespin valve GMR film 10 and a pair of electrodes 7, the GMR element 9 isconstituted. In addition, the electrodes 7 can be formed underneath thespin valve GMR film 10.

In a spin valve type GMR element 9, when an anti-ferromagnetic materialfilm of the present invention is used for fixation of magnetization ofone side ferromagnetic layer, since, as described above, primaryperformance of an anti-ferromagnetic material film 3 consisting of suchas an RMn alloy can be fully and stably exhibited, and exchange couplingforce sufficient at room temperature and high temperature region can beobtained stably, the magnetic fixation state of the pinning layerbecomes stable and strong, thus, excellent GMR characteristics can beobtained stably.

Next, one example of a reproducing MR head and a magneticrecording/reproducing combination head using thereof in which an MRelement (a GMR element, for example) of the above described example isapplied will be described with reference to FIG. 5 to FIG. 6.

As shown in FIG. 5, on one main surface of a substrate 21 composed ofAl₂ O₃.TiC and the like, through an insulating layer 22 consisting ofAl₂ O₃ and the like, a lower side magnetic shield layer 23 composed of asoft magnetic material is formed.

On the lower side magnetic shield layer 23, through a lower sidereproducing magnetic gap 24 composed of a non-magnetic insulating filmsuch as Al₂ O₃, a GMR element 9 shown, for example, in FIG. 4 is formed.

Numeral 25 in the figure is a hard magnetic film (hard bias film)consisting of CoPt alloy and the like which invest bias magnetic fieldto the spin valve GMR film 10. The bias film can be constituted by theanti-ferromagnetic material film. A pair of electrodes 7 are formed onthe hard magnetic film 25, and the spin valve GMR film 10 and a pair ofelectrodes 7 are electrically connected through the hard magnetic film25. The hard magnetic film 25 investing the bias magnetic field to thespin valve GMR film 10, as shown in FIG. 6, can be formed beforehand ona lower side reproducing magnetic gap 24. In this case, on the lowerside reproducing magnetic gap 24 including a pair of hard magnetic films25, the spin valve GMR film 10 is formed, and thereon a pair ofelectrodes 7 are formed.

On the GMR element 9, an upper side reproducing magnetic gap 26consisting of a non-magnetic insulating film such as Al₂ O₃ is formed.Further, thereon an upper side magnetic shield layer 27 consisting of asoft magnetic material is formed, thereby a shield type GMR head 28functioning as a reproducing head is constituted.

On a reproducing magnetic head consisting of the shield type GMR head28, a recording magnetic head comprising an induction type thin filmmagnetic head 29 is formed. An upper side magnetic shield layer 27 ofthe shield type GMR head 28 concurrently works as a lower recordingmagnetic pole of the induction type thin film magnetic head 29. On thelower recording magnetic pole 27 which concurrently works as the upperside magnetic shield layer, through a recording magnetic gap 30consisting of a non-magnetic insulating film such as Al₂ O₃, an upperrecording magnetic pole 31 patterned in a predetermined shape is formed.

With a reproducing head comprising such a shield type GMR head 28 and arecording head comprising an induction type thin film magnetic head 29,a magnetic recording/reproducing combination head 32 is constituted. Inaddition, the upper recording magnetic pole 31 can be formed byembedding inside a trench which is disposed on an insulating layerconsisting of SiO₂ and the like formed on a recording magnetic gap,thereby a narrow track can be realized with reproducibility. Themagnetic recording/reproducing combination head 32, by shape forming orseparating operation utilizing, for example, a semiconductor process,can be formed.

In the shield type GMR head 28 of the magnetic recording/reproducingcombination head described in the above example, a large exchangecoupling force and a high blocking temperature which an exchangecoupling film formed between the anti-ferromagnetic material film, whichcomprises RMn alloy, and the ferromagnetic material film show, can befully utilized. In addition, even when an AMR element of the presentinvention is applied in a reproducing magnetic head, a magneticrecording/reproducing combination head can be similarly formed.

Next, concrete embodiments of the present invention and their evaluatedresults will be explained.

Embodiment 1, 2

As raw material powder of R elements, Ir powder, Pt powder, Rh powder,Ni powder, Pd powder, Ru powder, Au powder of each average particlediameter of 20 μm are prepared. Besides, for Mn raw material powder, Mnpowder of an average particle diameter of 40 μm is prepared. Afterrespective raw material powder is compounded according to the compoundratio (raw material composition) shown in table 1 respectively, toprevent contamination from metal impurities, mixing operation isexecuted with a ball mill made of Nylon. Respective mixing operation isexecuted for 48 hours under a reduced pressure.

These respective mixed powder are sintered under a pressure of 25 MPausing a vacuum hot press apparatus. The hot press operation is executedat 1,150° C. immediate below the melting temperature of Mn.

Constituent phases of respective obtained target material is analysedwithin its plane with an XRD and an EPMA method. As a result, everytarget material is confirmed to include alloy phase and compound phaseformed between the R elements and Mn. Main alloy phase and main compoundphase of the respective target material are shown in Table 1. Further,the grain diameter of Mn existing as a single phase is investigated witha SEM method. The grain size of Mn in each target material is 30 μm atthe maximum and 20 μm at the average.

Then, after processing the above described respective target materialinto a target shape, a backing plate is soldered thereto to produce asputtering target respectively. After setting the respective sputteringtarget in a high frequency magnetron sputtering apparatus, ananti-ferromagnetic material film is formed in a film in a magnetic fieldwithout heating the substrate. The anti-ferromagnetic material film isformed in a film so as to form an exchange coupling film.

Specifically, on a Si (100) substrate covered with a thermally oxidizedfilm, a Ta substrate film of a thickness of 5 nm, a Co basedferromagnetic material film of a thickness of 5 nm, andanti-ferromagnetic material films of various compositions of a thicknessof 15 nm are sequentially formed.

Thus, each exchange coupling film is produced. At this stage, theexchange bias force is measured. However, concerning a Ni₅₀ Mn₅₀ filmand a Pd₅₀ Mn₅₀ film, since, without heat treatment, the exchangecoupling force can not be obtained, their exchange bias force aremeasured after heat treatment at condition of 270° C. and 5 hours.Obtained values are shown in Table 1 (embodiment 1).

As another embodiment of the present invention (embodiment 2), with theidentical processes except employing Mn powder of an average particlediameter of 150 μm, sputtering targets of the same composition areproduced, respectively. Each sputtering target according to embodiment 2is evaluated as identical with the embodiment 1. The results areconcurrently shown in Table 1 (embodiment 2).

Then, the constituent phases of each sputtering target according to theembodiment 2 are analysed within its plane with an XRD method and anEPMA method. There showed up identical alloy phases or compound phaseswith the embodiment 1, but, when measured with a SEM method, the grainsize of Mn turned out to be 100 μm at maximum, 40 μm at minimum, and 80μm at average.

Further, as a comparative example of the present invention, by usingeach raw material powder employed in the embodiment 1 and embodiment 2and by processing identically with the embodiment 1 and embodiment 2except that the hot pressing temperature is set at a temperature (1,000°C.) where any alloy phases and compound phases are not formed, eachsputtering target of identical composition is produced, respectively.When each sputtering target according to comparative example 1 isanalysed within its plane as to the constituent phase with an XRD methodand an EPMA method, there is no alloy phase or compound phase.

                  TABLE 1                                                         ______________________________________                                                                           Exchange Bias Force                             Raw                           ( × 80 A/m )                              Material                                                                              Target                          Compa-                                Com-    Com-           Primary                                                                              Em-  Em-  rative                           Sam- posi-   posi-   Primary                                                                              Com-   bodi-                                                                              bodi-                                                                              Ex-                              ple  tion    tion    Alloy  pound  ment ment ample                            No.  (at.%)  (at.%)  Phase  Phase  1    2    1                                ______________________________________                                        1    Ir22,   Ir.sub.22                                                                             IrMn   IrMn.sub.3                                                                           250  180  170                                   Mn78    Mn.sub.78                                                                             alloy                                                    2    Pt18,   Pt.sub.18                                                                             PtMn   PtMn.sub.3                                                                           190  140  140                                   Mn82    Mn.sub.82                                                                             alloy                                                    3    Rh20,   Rh.sub.20                                                                             RhMn   RhMn.sub.3                                                                           210  150  140                                   Mn80    Mn.sub.80                                                                             alloy                                                    4    Ir20,   Ir.sub.20                                                                             IrMn   IrMn.sub.3                                                                           260  180  170                                   Mn80    Mn.sub.80                                                                             alloy                                                    5    Ni40,   Ni.sub.40                                                                             NiMn   NiMn   250  180  180                                   Mn60    Mn.sub.60                                                                             alloy                                                    6    Pd40,   Pd.sub.40                                                                             PdMn   PdMn   180  130  120                                   Mn60    Mn.sub.60                                                                             alloy                                                    7    Pt20,   Pt.sub.20                                                                             PtPdMn (Pt,Pd)Mn                                                                            250  220  210                                   Pd20,   Pd.sub.20                                                                             alloy  compound                                               Mn60    Mn60                                                             8    Pt20,   Pt.sub.20                                                                             PtRuMn (Pt,Ru)Mn                                                                            230  200  180                                   Ru20,   Ru.sub.20                                                                             alloy  compound                                               Mn60    Mn.sub.60                                                        9    P20,    Pd.sub.20                                                                             PdRuMn (Pd,Ru)                                                                              200  170  160                                   Ru20,   Ru.sub.20                                                                             alloy  Mn                                                     Mn60    Mn.sub.60      compound                                          10   Au10,   Au.sub.10                                                                             AuPtMn (Au,Pt)Mn                                                                            180  160  160                                   Pt10,   Pt.sub.10                                                                             alloy  compound                                               Mn80    Mn80                                                             11   Rh10,   Rh.sub.10                                                                             RhRuMn (Rh,Ru)                                                                              240  210  200                                   Ru10,   Ru.sub.10                                                                             alloy  Mn                                                     Mn80    Mn.sub.80      compound                                          12   Rh10,   Rh.sub.10                                                                             RhPtMn (Rh,Pt)Mn                                                                            240  200  210                                   Pt10,   Pt.sup.10                                                                             alloy  compound                                               Mn80    Mn.sub.80                                                        ______________________________________                                    

As evident from Table 1, all of exchange coupling films which includethe anti-ferromagnetic material films formed in films using thesputtering target of the present invention displayed large exchangecoupling forces, thus, exellent performance is displayed. On thecontrary, in the case of exchange coupling film formed employing eachsputtering target of comparative example, only small exchange couplingforce can be obtained.

Next, a composition variation accompanying lapse of sputtering time ofeach anti-ferromagnetic material film according to the above describedembodiment 1 is investigated. The composition variation is investigatedby measuring the compositions of the anti-ferromagnetic material film ofsputtering initial stage (after 1 hour) and the anti-ferromagneticmaterial film formed after 20 hours sputtering with an X-rayfluorescence analysis method. Their results are shown in Table 2.

                  TABLE 2                                                         ______________________________________                                                             Deviation of Film                                                     Target  Composition(at. %)                                                      Composition                                                                             After 1  After 20                                           Sample No.                                                                            (at. %)   hour     hours                                       ______________________________________                                        Embodiment                                                                             1         Ir.sub.22 Mn.sub.78                                                                     Ir.sub.22 Mn.sub.78                                                                  Ir.sub.21.8 Mn.sub.78.2                   1        2         Pt.sub.18 Mn.sub.82                                                                     Pt.sub.18 Mn.sub.82                                                                  Pt.sub.18.3                                                                   Mn.sub.81.7                                        3         Rh.sub.20 Mn.sub.80                                                                     Rh.sub.20 Mn.sub.80                                                                  Rh.sub.19.5 Mn.sub.80.5                            4         Ir.sub.20 Mn.sub.80                                                                     Ir.sub.20 Mn.sub.80                                                                  Ir.sub.20.3 Mn.sub.79.7                            5         Ni.sub.40 Mn.sub.60                                                                     Ni.sub.50 Mn.sub.50                                                                  Ni.sub.49.5 Mn.sub.50.5                            6         Pd.sub.40 Mn.sub.60                                                                     Pd.sub.50 Mn.sub.50                                                                  Pd.sub.49.5 Mn.sub.50.5                   Embodiment                                                                             1         Ir.sub.22 Mn.sub.78                                                                     Ir.sub.25 Mn.sub.75                                                                  Ir.sub.30 Mn.sub.70                       Comparative                                                                            1         Ir.sub.22 Mn.sub.78                                                                     Ir.sub.21 Mn.sub.79                                                                  Ir.sub.27 Mn.sub.73                       Example 1                                                                     ______________________________________                                    

Further, as to an anti-ferromagnetic material film (IrMn alloy film)formed into a film by employing a sputtering target according tospecimen 1 of the embodiment 1 and an anti-ferromagnetic material film(IrMn alloy film) formed into a film using a sputtering target of thecomparative example 1, the composition distribution within a film planeis investigated. The measurement were executed on a Si substrate at acentral point (A point) and other four points (B, C, D, E point)separated 3 cm from the central point toward periphery along diagonals.The obtained results are shown in Table 3.

                  TABLE 3                                                         ______________________________________                                               Target Ir Composition at Each Point within                                    Composi-                                                                             a Substrate (at. %)                                                      tion             B     C    D                                                 (at. %)  A point point point                                                                              point                                                                              E point                             ______________________________________                                        Embodiment                                                                             Ir.sub.22 Mn.sub.78                                                                    22.0    21.8  21.7 21.6 21.5                                Comparative                                                                            Ir.sub.22 Mn.sub.78                                                                    25.0    23.8  23.5 24.1 23.4                                Example 1                                                                     ______________________________________                                    

As evident from Table 2 and Table 3, an anti-ferromagnetic material filmformed using a sputtering target of the present invention displays asmall composition deviation accompanying the lapse of sputtering timeand is excellent in homogeneity of composition distribution within asubstrate plane.

Embodiment 3

With an identical method as the embodiment 1, IrMn targets, RhMntargets, PtMn targets of various compositions are produced respectively.With each from IrMn target, RhMn target, PtMn target of these variouscompositions, an exchange coupling film is manufactured with identicalmanner as the embodiment 1. Exchange coupling force of each exchangecoupling film is measured, and composition dependency of the exchangecoupling force is investigated. The result is shown in FIG. 7.

As evident from FIG. 7, it is understood that each exchange couplingfilm comprising an anti-ferromagnetic material film formed into a filmusing a sputtering target of the present invention displays sufficientexchange coupling force in a broad composition range.

Embodiment 4

With an identical process as embodiment 1 except that Mn powderpossessing average particle diameter shown in Table 4 is used, asputtering target respectively different in the particle diameter of Mnas shown in Table 4 is manufactured.

Oxygen content of obtained each sputtering target is measured and, afterforming into a film as identical manner as embodiment 1, the exchangebias force is measured. Further, with the identical method as that ofthe embodiment 1, the composition distribution within a film plane isinvestigated. The results are shown in Table 4.

                                      TABLE 4                                     __________________________________________________________________________             Average                                                                       Particle                                                                      Diameter                                                                           Grain size           Ex-                                                 of Raw                                                                             of Mn Ir Composition at Each                                                                       change                                         Target                                                                             Material                                                                           Particle in                                                                         Point within a Substrate                                                                     Bias                                       Sam-                                                                              Compo-                                                                             Mn   Target (μm)                                                                      (at. %)        Force                                      ple sition                                                                             Powder                                                                             aver-                                                                            maxi-                                                                            A  B  C  D  E  (× 80                                No. (at. % )                                                                           (μm)                                                                            age                                                                              mum                                                                              point                                                                            point                                                                            point                                                                            point                                                                            point                                                                            A/m)                                       __________________________________________________________________________    1   Ir.sub.22 Mn.sub.78                                                                10   <10                                                                              <10                                                                              22.0                                                                             21.7                                                                             21.6                                                                             21.7                                                                             21.5                                                                             200                                        2   Ir.sub.22 Mn.sub.78                                                                40   20 30 22.0                                                                             21.8                                                                             21.6                                                                             21.5                                                                             21.6                                                                             250                                        3   Ir.sub.22 Mn.sub.78                                                                80   30 40 22.3                                                                             22.0                                                                             22.2                                                                             21.8                                                                             22.0                                                                             250                                        4   Ir.sub.22 Mn.sub.78                                                                150  80 130                                                                              25.0                                                                             23.8                                                                             23.5                                                                             24.1                                                                             23.4                                                                             240                                        __________________________________________________________________________

As evident from Table 4, the film compositions formed into filmsemploying the Mn grains large in the maximum size and average sizedisplay large variations in their substrate planes, thereby it can beunderstood that these targets cause problems in massproduction. On thecontrary, the films obtained by using the sputtering targets small intheir maximum grain size and average grain size do not show problem asto the composition variation in their substrate planes, but theirexchange bias forces tend to decrease.

Embodiment 5

Each sputtering target shown in Table 5 is manufactured employing thesintering method identical with the embodiment 1 and with, other thanthat, the melting method, respectively. Processability and gas componentconcentrations (included gas concentrations of both of oxygen andcarbon) of each sputtering target are investigated. Further, afterforming the exchange coupling film with the identical way as theembodiment 1, the exchange bias force and the blocking temperature ofeach exchange coupling film are measured. These results are shown inTable 5. In addition, the constituent phases of each sputtering targetaccording to embodiment 3 are identical with those of the embodiment 1.

Besides, as a comparative example 2 to the present invention, eachsputtering target is manufactured with the sintering method identicalwith that of the above described embodiments except that raw materialpowder relatively rich in carbon impurity quantity is employed andmixing operation is executed in air. Further, each sputtering target ismanufactured with the melting method identical with that of the abovedescribed embodiments except that raw material powder relatively rich incarbon impurity is employed and degassing time during melting is setshort than those of the embodiments. As to each sputtering targetaccording to the comparative example, the processability, gas componentconcentrations, and the exchange bias force of the exchange couplingfilm are measured. These results are also shown in Table 5.

                  TABLE 5                                                         ______________________________________                                                                        Ex-                                                                           change                                        Target      Manu-   Gas Component                                                                             Bias  Blocking                                Compo-      fact-   Concentration                                                                             Force Temper-                                 sition      uring   (wt. %)     (× 80                                                                         ature                                   (at. %)     Method  oxygen  carbon                                                                              A/m)  (° C.)                         ______________________________________                                        Embodi-                                                                              Ir.sub.22 Mn.sub.78                                                                    Sinter- 0.600 0.200 250   290                                 ment 5          ing                                                                           Method                                                               Ir.sub.22 Mn.sub.78                                                                    Melting 0.028 0.005 250   280                                                 Method                                                               Pt.sub.18 Mn.sub.82                                                                    Sinter- 0.580 0.160 180   390                                                 ing                                                                           Method                                                               Pt.sub.18 Mn.sub.82                                                                    Melting 0.025 0.005 180   400                                                 Method                                                        Compara                                                                              Ir.sub.22 Mn.sub.78                                                                    Sinter- 3.120 1.010 180   210                                 tive            ing                                                           Example         Method                                                        2      Ir.sub.22 Mn.sub.78                                                                    Melting 1.580 0.980 180   200                                                 Method                                                               Pt.sub.18 Mn.sub.82                                                                    Sinter- 2.140 1.220 130   350                                                 ing                                                                           Method                                                               Pt.sub.18 Mn.sub.82                                                                    Melting 1.760 0.790 130   360                                                 Method                                                        ______________________________________                                    

As evident from Table 5, by employing the sputtering targets of thepresent invention in which both of the oxygen content and the carboncontent are reduced, performance of the exchange coupling filmscomprising the anti-ferromagnetic material films formed using thereofcan be enhanced.

Embodiment 6

In this embodiment, with an exchange coupling film formed between ananti-ferromagnetic material film, which is formed into a film using anidentical sputtering target as the example 1, and a ferromagneticmaterial film, respective GMR element comprising respective spin valvefilm shown in FIG. 4 or FIG. 6 and magnetic heads using thereof aremanufactured.

In the spin valve GMR film 10, Co₉₀ Fe₁₀ films of respective thicknessof 3 nm, 2 nm, are used for ferromagnetic layers 11, 13 respectively,and Cu film of a thickness of 3 nm for the non-magnetic layer 12. EachCo₉₀ Fe₁₀ film now formed into a film comprised a crystal structure of aface-centered cubic crystal system. For an anti-ferromagnetic materialfilm 3, each anti-ferromagnetic material film (film thickness of 8 nm)produced according to the above described embodiment 1 or embodiment 3is used.

In addition, for the magnetic substrate layer 14, a laminate film formedbetween a Co₈₈ Zr₅ Nb₇ film of a thickness of 10 nm and a Ni₈₀ Fe₂₀ filmof a thickness of 2 nm is used, for the electrode 7, a Cu film of athickness of 0.1 nm is used, and, for the protective film 15, a Ta filmof a thickness of 20 nm is used, respectively. Further, for the hardmagnetic layer 25, a Co₈₃ Pt₁₇ film of a thickness of 40 nm is used.

Film formation of the ferromagnetic layers 11, 13, the non-magneticlayer 12, and the anti-ferromagnetic material film 3 is executed in amagnetic field, further, by heat treating them in a magnetic fieldthereafter, a uniaxial magnetic anisotropy is given to the exchangecoupling between the ferromagnetic layer 13 and the anti-ferromagneticmaterial film 3. In addition, the magnetic substrate layer 14 is alsoheat treated after film formation in the magnetic field and is investeda uniaxial magnetic anisotropy, and, by magnetizing the hard magneticlayer 25, the uniaxial magnetic anisotropy is further enhanced. Finally,by processing the element according to a conventional semiconductorprocess, a GMR element and a magnetic head using thereof are produced.

While applying an external magnetic field from outside to the GMRelement manufactured according to the present embodiment, their magneticfield response performance are checked. Output stable at equal level ormore than that of a GMR element in which a γ-FeMn alloy is used in theanti-ferromagnetic material film can be obtained. In addition, noBarkhausen noise due to magnetic wall shift is detected. Furthermore,compared with the GMR element in which γ-FeMn alloy is used for theanti-ferromagnetic material film, due to excellent corrosion resistivityof the anti-ferromagnetic material film, in addition, due to highblocking temperature of the exchange coupling film and large exchangecoupling force, a highly sensitive GMR element, in which stable outputcan be realized, can be manufactured with high yield.

Further, in a magnetic head comprising such a GMR element, when an IrMnbased anti-ferromagnetic material film highly resistant in corrosion isemployed, 0.1 μm depth, which was impossible due to corrosion when FeMnis employed, was made possible, thus, a large reproducing output can beobtained.

Embodiment 7

Sputtering targets are manufactured with an identical process as theembodiment 1 using IrMn alloy and IrMn alloys respectively added withone additional element from Ge, Si, Ga, Al, Zn, Hf, Zr, Ti.

With each sputtering target thus obtained, after manufacturing eachexchange coupling film sample with an identical method as the embodiment1, corrosion resistivity test is executed on each sample. In thecorrosion resistivity test, after immersing above obtained each samplein water for 24 hours, incidence of corrosion pit was measured. Theresults are shown in FIG. 8.

In addition, as comparative example to the present invention, samplesemploying anti-ferromagnetic material films comprising of (Fe₀.5Mn₀.5)₈₉.5 Ir₁₀.5 alloy and Fe₅₀ Mn₅₀ alloy instead of IrMn alloy areexposed to an identical corrosion resistivity test. The results areshown in FIG. 8.

As evident from the results of the corrosion resistivity test shown inFIG. 8, by addition of other elements to the IrMn alloy, it is foundthat incidence of the corrosion pit are reduced.

In addition, in FIG. 9 and FIG. 10, measured results of the exchangebias magnetic field and the blocking temperature of each sample areshown. As evident from FIG. 9 and FIG. 10, both of the exchange biasmagnetic field and the blocking temperature are enhanced.

According to a sputtering target of the present invention, ananti-ferromagnetic material film comprising a Mn alloy excellent incorrosion resistivity and thermal performance can be stabilized in itsfilm composition and film quality. Therefore, an anti-ferromagneticmaterial film, in which sufficient exchange coupling force can beobtained stably, can be realized with reproducibility. Such ananti-ferromagnetic material film of the present invention can be appliedeffectively in a magneto-resistance effect element and the like.Further, according to a magneto-resistance effect element employing ananti-ferromagnetic material film of the present invention, stableperformance as well as output can be obtained with reproducibility.

What is claimed is:
 1. A sputtering target consisting essentially of Mnand at least one kind of R element selected from the group consisting ofNi, Pd, Pt, Co, Rh, Ir, V, Nb, Ta, Cu, Ag, Ru, Os, Cr, Mo, W, and Re,wherein the sputtering target comprises at least one member selectedfrom the group consisting of an alloy phase and a compound phase formedbetween the R element and Mn as at least a part of the target texture.2. The sputtering target as set forth in claim 1, wherein an oxygencontent of the sputtering target is 1 weight % or less.
 3. Thesputtering target as set forth in claim 1, wherein an oxygen content ofthe sputtering target is 0.7 weight % or less.
 4. The sputtering targetas set forth in claim 1, wherein an oxygen content of the sputteringtarget is 0.1 weight % or less.
 5. The sputtering target as set forth inclaim 1, wherein an oxygen content of the sputtering target is 0.025weight % or less.
 6. The sputtering target as set forth in claim 1,wherein the maximum diameter of the Mn grain, other than the Mnconstituting the alloy phase and the compound phase, is 50 μm or lessand wherein the average grain diameter of the Mn is in the range of from10 to 40 μm.
 7. The sputtering target as set forth in claim 1, wherein acarbon content of the sputtering target is 0.3 weight % or less.
 8. Thesputtering target as set forth in claim 1, wherein a carbon content ofthe sputtering target is 0.2 weight % or less.
 9. The sputtering targetas set forth in claim 1, wherein a carbon content of the sputteringtarget is 0.01 weight % or less.
 10. The sputtering target as set forthin claim 1, wherein a carbon content of the sputtering target is 0.005weight % or less.
 11. The sputtering target as set forth in claim 1,wherein the R element is at least one selected from the group consistingof Ir, Pt, and Pd.
 12. The sputtering target as set forth in claim 1,wherein the relative density of the sputtering target is 90% or more.13. The sputtering target as set forth in claim 12, wherein thesputtering target is obtained by sintering.
 14. The sputtering target asset forth in claim 12, wherein the sputtering target is obtained by amelting method.
 15. The sputtering target as set forth in claim 1,wherein the sputtering target contains 30 atomic % or more of Mn. 16.The sputtering target as set forth in claim 1, further comprising atleast one element selected from the group consisting of Be, Ti, Zr, Hf,Zn, Cd, Al, Ga, In, Si, Ge, Sn, and N.
 17. A sputtering targetconsisting essentially of Mn and at least one kind of R element selectedfrom the group consisting of Ni, Pd, Pt, Co, Rh, Ir, V, Nb, Ta, Cu, Ag,Ru, Os, Cr, Mo, W, and Re, wherein an oxygen content of the sputteringtarget is 1 weight % or less.
 18. The sputtering target as set forth inclaim 17, wherein an oxygen content of the sputtering target is 0.7weight % or less.
 19. The sputtering target as set forth in claim 17,wherein an oxygen content of the sputtering target is 0.1 weight % orless.
 20. The sputtering target as set forth in claim 17, wherein anoxygen content of the sputtering target is 0.025 weight % or less. 21.The sputtering target as set forth in claim 17, wherein a carbon contentof the sputtering target is 0.3 weight % or less.
 22. The sputteringtarget as set forth in claim 17, wherein a carbon content of thesputtering target is 0.2 weight % or less.
 23. The sputtering target asset forth in claim 17, wherein a carbon content of the sputtering targetis 0.01 weight % or less.
 24. The sputtering target as set forth inclaim 17, wherein a carbon content of the sputtering target is 0.005weight % or less.
 25. The sputtering target as set forth in claim 17,wherein the R element is at least one selected from the group consistingof Ir, Pt, and Pd.
 26. The sputtering target as set forth in claim 17,wherein the relative density of the sputtering target is 90% or more.27. The sputtering target as set forth in claim 26, wherein thesputtering target is obtained by sintering.
 28. The sputtering target asset forth in claim 26, wherein the sputtering target is obtained by amelting method.
 29. The sputtering target as set forth in claim 17,wherein the sputtering target contains 30 atomic % or more of Mn. 30.The sputtering target as set forth in claim 17, further comprising atleast one element selected from the group consisting of Be, Ti, Zr, Hf,Zn, Cd, Al, Ga, In, Si, Ge, Sn, and N.
 31. An anti-ferromagneticmaterial film formed into a film by a sputtering method with thesputtering target as set forth in claim
 1. 32. A magneto-resistanceeffect element comprising an anti-ferromagnetic material film as setforth in claim
 31. 33. A magneto-resistance effect element comprisingthe anti-ferromagnetic material film as set forth in claim 31 and aferromagnetic material film exchange-coupled with the anti-ferromagneticmaterial film.
 34. A magneto-resistance effect element comprising theanti-ferromagnetic material film as set forth in claim 31, a firstferromagnetic layer exchange-coupled with the anti-ferromagneticmaterial film, and a second ferromagnetic layer stacked on the firstferromagnetic layer through a non-magnetic layer.
 35. Themagneto-resistance effect element as set forth in claim 32, wherein theanti-ferromagnetic material film has a thickness in the range of 3 to 15nm.
 36. The magneto-resistance effect element as set forth in claim 32,wherein the anti-ferromagnetic material film has a thickness of 10 nm orless.
 37. The magneto-resistance effect element as set forth in claim33, wherein the ferromagnetic material film has a thickness in the rangeof 1 to 3 nm.
 38. An anti-ferromagnetic material film formed into a filmby a sputtering method with the sputtering target as set forth in claim17.
 39. A magneto-resistance effect element comprising ananti-ferromagnetic material film as set forth in claim
 38. 40. Amagneto-resistance effect element comprising the anti-ferromagneticmaterial film as set forth in claim 38 and a ferromagnetic material filmexchange-coupled with the anti-ferromagnetic material film.
 41. Amagneto-resistance effect element comprising the anti-ferromagneticmaterial film as set forth in claim 38, a first ferromagnetic layerexchange-coupled with the anti-ferromagnetic material film, and a secondferromagnetic layer stacked on the first ferromagnetic layer through anon-magnetic layer.
 42. The magneto-resistance effect element as setforth in claim 39, wherein the anti-ferromagnetic material film has athickness in the range of 3 to 15 nm.
 43. The magneto-resistance effectelement as set forth in claim 39, wherein the anti-ferromagneticmaterial film has a thickness of 10 nm or less.
 44. Themagneto-resistance effect element as set forth in claim 40, wherein theferromagnetic material film has a thickness in the range of 1 to 3 nm.45. A magnetic head comprising a magneto-resistance effect element asset forth in claim
 32. 46. A magnetic recording apparatus comprising amagnetic head as set forth in claim
 45. 47. The magnetic recordingapparatus as set forth in claim 46, wherein the magnetic recordingapparatus is an HDD recording apparatus.
 48. A magnetic memory apparatuscomprising a magneto-resistance effect element as set forth in claim 32.49. A magnetic memory apparatus comprising a magneto-resistance effectelement as set forth in claim
 39. 50. The magnetic memory apparatus asset forth in claim 48, wherein the magnetic memory is amagneto-resistance effect memory.
 51. The magnetic memory apparatus asset forth in claim 49, wherein the magnetic memory is amagneto-resistance effect memory.
 52. A magnetic sensor comprising amagneto-resistance effect element as set forth in claim
 32. 53. Amagnetic sensor comprising a magneto-resistance effect element as setforth in claim
 39. 54. A magnetic head comprising a magneto-resistanceeffect element as set forth in claim
 38. 55. A magnetic recordingapparatus comprising a magnetic head as set forth in claim
 54. 56. Themagnetic recording apparatus as set forth in claim 55, wherein themagnetic recording apparatus is an HDD recording apparatus.